Explain internal and external indeterminancy.

Following table summarizes the internal and external indeterminacy in relation to the overall structural indeterminacy.

Aspect	Internal Indeterminacy (I.I)	External Indeterminacy (E.I)
Definition	The excess number of internal forces that cause a structure to be indeterminate.	The excess number of external reactions that make the structure indeterminate.
Formula	I.I= i−E.I	E.I= r−e
Where	i = total indeterminacy	r = number of support reactions
	E.I = external indeterminacy	e = number of equilibrium conditions
Equilibrium Conditions (e)	e=3 for plane frames	e=6 for space frames
Total Indeterminacy	i=I.I+E.I